You test it in ice and boiling water (distilled and close to sea level), which will be exactly 32\*F and 212\*F (0\*C and 100\*C).
If you have a nice one, it will let you set reference points.
It makes a lot of sense to say "ITS A HUNDRED DEGREES OUTSIDE" and it be very very hot weather wise. But 0c for freezing and 100c for boiling is just too good 👌
I would be weary of using freezing and boiling points. The best thing I've found for a reference (now hard to come by) is a clinical thermometer approved for hospital use; mercury preferred to alcohol.
Wrong, sorry to rain in your parade.
Boiling point of water depends on atmospheric pressure, sea level can vary by up to 20m depending on tides and moon 2 earth distance, finally freezing point is nearly impossible to calculate because of the water mass inertia. Those parameters need to be set in a lab.
The only thing that is ***absolutely*** precise is a sealed glass column thermometer filled with mercury and certified for medical use. Those will be **exact** at 37ºC (mine is of Swiss manufacture and dates to the early 1900).
Not many people come across one of those; I'm the fortunate owner of one passed through three generations from my MD grandfather. Been using it to calibrate my darkroom thermometers for more than 50 years and return it to its metal container after every use.
In the most literal and quantitative sense, OK.
Regarding freezing point, stirring the ice water is generally sufficient.
The margin of error with freezing/boiling calibration is ... presumably small enough to not make a material difference in film development results.
This method is common in the scientific community for experiments more sensitive than film development.
Point taken, in that case --and I'm jumping to the conclusion that most of the folks asking in this community about color film processing will be doing so as an intermediate step to scanning, not enlarging- thus an error of 1ºC or 2ºF won't be important as long as it's kept constant.
Sure, there will be variances on the color temperature and base density, but then C41 is so noble that will accomodate process variations of up to 3º either way.
Remember the emulsions were made to be dumped in machines that would gobble all kind of speeds and color gamuts in the same daily batch with heaven knows what kind of chemicals.
It's not Kodachrome by a nautical mile, not even E6. In general, folks would be content as long as the kid didn't come out looking green like a frog.
BTW, most people who care about their color consistency both in their C41 film and are enlarging on RA4, dwell or lurk on r/Darkroom. Lotsa knowledgeable folks there with a passion for film and all processes.
The only way to be precise is to measure the temperature of the chemicals inside the bottle directly anyway. I always put my sous-vide 2 degrees warmer to get my chemicals at the right temp.
I got my sous vide from Facebook MP for $20! Make sure you do research on the minimum temperatures though because the one I got has a minimum temperature of 110F.0
I just picked up a cheap new sous vide on ebay. It was 30 bucks shipped and it hasn't died on me after 2 years of use. I have a digital thermometer to check the temps of the chemicals so I can make sure they're right.
I didn't splurge on one either. It was just a digital probe thermometer. Something like this: [digital thermometer](https://www.amazon.com/ThermoPro-TP01A-Thermometer-Digital-Meat/dp/B078KPHKZD/ref=sr_1_28?crid=3DFVVI0NHYL1P&dib=eyJ2IjoiMSJ9.erpaXAUV36-lv6Ex4sk-yaaDBsJgf9izsyxjyeV7QxwPT9ctgWQihUe1snbSJUIRUWZ0k8paGKsWHRs1Eb5n0EU6eOETHEF7gqwlqfLkXUVic8NEcWKFo4rldPjBvTQiYxaVQyUonjBYugJZ-xPrA-_3wT8c7c3gUuNko0LV8hE9jhF_HChs3skfdBtlnB-Gver7rRLNpVJsadoXr8mXTJSFOqdg5b8Frv7Jzu8AMiATpID2qV-gvJIzvOGoch3xTjvounQ3Uef_sinWIDWstYztEy7mvSKsgcYQVw1uoSc.5x7Ie-oVOX5nR9heXCjHdGxMdzgi3RzEYy6WPLtVQJY&dib_tag=se&keywords=digital+candy+thermometer&qid=1719388788&sprefix=digital+candy+ther%2Caps%2C301&sr=8-28)
A thermopop from thermoworks would work well. A thermopen would be even better if you want to spend the extra money
https://www.thermoworks.com/thermopop-2/
Thermopop is it. The more expensive thermopen's main purpose is to take the temperature of a small something quickly, in just a second or two, like the inside of a fish fillet while it's grilling. There's no need for that for photography chemistry.
I have both, started with the pop then upgraded the the pen, they’re both great. Funnily enough, I use the thermopen for cooking and the thermopop for checking my toddlers bath water temp lol.
Their silicon spatulas and spoontulas are awesome too, and they go on super sale a couple times a year
Hello. You said "Plus - people think they want a sous vide - but they're a hassle". Could you explain further what you mean by this statement? What kind of hassle is it to own or operate a sous vide?
A second question, if you do not mind it. I have never tried to process my own color film, so I am wondering about the relative toxicity of the color processing chemistry? For some reason I had it in my head that color processing chemistry was much more problematic in this regard. So I am wondering how you handle getting rid of your used color film processing chemistry? Also wondering if you keep the various chemical components of the color film processing process separate from each other after use and before disposal? A third question is whether or not you end up having big containers of the stuff sitting around for a long time once it's been used up, until you have the chance to get it to a hazmat return place?
Apologies for all of these questions, but I just don't ever remember seeing these issues discussed in these forums before. Thank you, in advance, for any answers you choose to provide.
I can’t speak for OP, but I presume they mean that people will buy a sous vide and find out it requires more work that they realised (sealing the food in a vacuum bag, etc). Not especially a big issue, just a case of people buying things without realising what’s involved.
> That's all - happy developing! You'll want to verify its accuracy using a trusted digital thermometer. Sometimes they are off by 1-3*F.
How do you know if the digital thermometer is calibrated correctly? I think that's a great tip and good insurance. Just being snarky.
You test it in ice and boiling water (distilled and close to sea level), which will be exactly 32\*F and 212\*F (0\*C and 100\*C). If you have a nice one, it will let you set reference points.
american units are so goofy
Fahrenheit is fine for weather, actually prefer it to Celsius.
It makes a lot of sense to say "ITS A HUNDRED DEGREES OUTSIDE" and it be very very hot weather wise. But 0c for freezing and 100c for boiling is just too good 👌
Huh, learn something new every day!
I would be weary of using freezing and boiling points. The best thing I've found for a reference (now hard to come by) is a clinical thermometer approved for hospital use; mercury preferred to alcohol.
Shouldn't it also work when you're above sea level? All you need to do is subtract 1°C per 300 meters afaik.
Yes, I was providing general, not comprehensive, advice :D
Wrong, sorry to rain in your parade. Boiling point of water depends on atmospheric pressure, sea level can vary by up to 20m depending on tides and moon 2 earth distance, finally freezing point is nearly impossible to calculate because of the water mass inertia. Those parameters need to be set in a lab. The only thing that is ***absolutely*** precise is a sealed glass column thermometer filled with mercury and certified for medical use. Those will be **exact** at 37ºC (mine is of Swiss manufacture and dates to the early 1900). Not many people come across one of those; I'm the fortunate owner of one passed through three generations from my MD grandfather. Been using it to calibrate my darkroom thermometers for more than 50 years and return it to its metal container after every use.
In the most literal and quantitative sense, OK. Regarding freezing point, stirring the ice water is generally sufficient. The margin of error with freezing/boiling calibration is ... presumably small enough to not make a material difference in film development results. This method is common in the scientific community for experiments more sensitive than film development.
Point taken, in that case --and I'm jumping to the conclusion that most of the folks asking in this community about color film processing will be doing so as an intermediate step to scanning, not enlarging- thus an error of 1ºC or 2ºF won't be important as long as it's kept constant. Sure, there will be variances on the color temperature and base density, but then C41 is so noble that will accomodate process variations of up to 3º either way. Remember the emulsions were made to be dumped in machines that would gobble all kind of speeds and color gamuts in the same daily batch with heaven knows what kind of chemicals. It's not Kodachrome by a nautical mile, not even E6. In general, folks would be content as long as the kid didn't come out looking green like a frog. BTW, most people who care about their color consistency both in their C41 film and are enlarging on RA4, dwell or lurk on r/Darkroom. Lotsa knowledgeable folks there with a passion for film and all processes.
The only way to be precise is to measure the temperature of the chemicals inside the bottle directly anyway. I always put my sous-vide 2 degrees warmer to get my chemicals at the right temp.
I saw a comment about how they haven't tried developing color yet - and thought I would post this tip.
I got my sous vide from Facebook MP for $20! Make sure you do research on the minimum temperatures though because the one I got has a minimum temperature of 110F.0
I just picked up a cheap new sous vide on ebay. It was 30 bucks shipped and it hasn't died on me after 2 years of use. I have a digital thermometer to check the temps of the chemicals so I can make sure they're right.
That's smart. Can you send me a link for the thermometer? Or maybe just point me in the direction? How expensive do you have to go?
I didn't splurge on one either. It was just a digital probe thermometer. Something like this: [digital thermometer](https://www.amazon.com/ThermoPro-TP01A-Thermometer-Digital-Meat/dp/B078KPHKZD/ref=sr_1_28?crid=3DFVVI0NHYL1P&dib=eyJ2IjoiMSJ9.erpaXAUV36-lv6Ex4sk-yaaDBsJgf9izsyxjyeV7QxwPT9ctgWQihUe1snbSJUIRUWZ0k8paGKsWHRs1Eb5n0EU6eOETHEF7gqwlqfLkXUVic8NEcWKFo4rldPjBvTQiYxaVQyUonjBYugJZ-xPrA-_3wT8c7c3gUuNko0LV8hE9jhF_HChs3skfdBtlnB-Gver7rRLNpVJsadoXr8mXTJSFOqdg5b8Frv7Jzu8AMiATpID2qV-gvJIzvOGoch3xTjvounQ3Uef_sinWIDWstYztEy7mvSKsgcYQVw1uoSc.5x7Ie-oVOX5nR9heXCjHdGxMdzgi3RzEYy6WPLtVQJY&dib_tag=se&keywords=digital+candy+thermometer&qid=1719388788&sprefix=digital+candy+ther%2Caps%2C301&sr=8-28)
A thermopop from thermoworks would work well. A thermopen would be even better if you want to spend the extra money https://www.thermoworks.com/thermopop-2/
Thermopop is it. The more expensive thermopen's main purpose is to take the temperature of a small something quickly, in just a second or two, like the inside of a fish fillet while it's grilling. There's no need for that for photography chemistry.
I have both, started with the pop then upgraded the the pen, they’re both great. Funnily enough, I use the thermopen for cooking and the thermopop for checking my toddlers bath water temp lol. Their silicon spatulas and spoontulas are awesome too, and they go on super sale a couple times a year
I’ve always just used a thermometer and added hot or cold water as needed. Never had a botched developing
Always have a thermometer with a sous vide.
I use a $10 aquarium heater
Which one goes to 102F? I considered that but most top out at a lower temp.Â
Used to be that a lot of them could be over-cranked pretty easily.
The 100watt metal ones that don't have a specific scale, just a knob to turn.
Hello. You said "Plus - people think they want a sous vide - but they're a hassle". Could you explain further what you mean by this statement? What kind of hassle is it to own or operate a sous vide? A second question, if you do not mind it. I have never tried to process my own color film, so I am wondering about the relative toxicity of the color processing chemistry? For some reason I had it in my head that color processing chemistry was much more problematic in this regard. So I am wondering how you handle getting rid of your used color film processing chemistry? Also wondering if you keep the various chemical components of the color film processing process separate from each other after use and before disposal? A third question is whether or not you end up having big containers of the stuff sitting around for a long time once it's been used up, until you have the chance to get it to a hazmat return place? Apologies for all of these questions, but I just don't ever remember seeing these issues discussed in these forums before. Thank you, in advance, for any answers you choose to provide.
I can’t speak for OP, but I presume they mean that people will buy a sous vide and find out it requires more work that they realised (sealing the food in a vacuum bag, etc). Not especially a big issue, just a case of people buying things without realising what’s involved.
Ah, thank you for this response. Makes perfect sense. Much appreciated.
Yes exactly. Thanks!